even if you delete them, they remain in the interface. i guess they're too spread out that way? the interface overhaul made it easy to view things like this though - all ads (not all but deleted), all time, sorted by ctr...

I just make periodic dumps of my accounts from AdWords Editor, and call 'em up when I need to. But you have to be careful not to accidentally post an old campaign. You can dump out of AdWords Editor into Excel (csv) files - that's probably as good as you're gonna get.